BS EN ISO 6874-2015 pdf download.Dentistry一Polymer-based pit and fissure sealants.
S Sampling
The test sample shall consist of a retail package, or packages, from the same batch containing sufficient
material (a minimum of 20 g) to carry out the specified tests and repeat tests. if necessary.
6 Test methods
6.1 Inspection
Inspect visually to check that requirements specified in laue2 have been met.
6.2 Test conditions
Unless specified otherwise by the manufacturer, prepare and test all specimens at (23 ± 2) C. Control the relative humidity to ensure that It remains greater than 30 % at all times. It the material was refrigerated for storage, allow It to attain (23 t 2) C before use.
For the preparation of class 2 materIals, reference shall be made to the manufacturer’s instructions Isce II e) and g) that state the external energy source or sources recommended for the materials to be tested. Care shall be taken to ensure that the source is in a satisfactory operating condition.
NOTE See also ISO 10650 (all parLs)
6.3 PreparatIon of test specimens
Mix or otherwise prepare the material in accordance with the manufacturers instructions and the test conditions specified in 62.
6.4 WorkIng time. Class 1 sealant
6.4.1 Apparatus
6.4.1.1 Thermometry apparatus, as shown in Figure 1.
The apparatus consists of a piece of polyethylene (or similar material) tubing. A. located on a block of polyamide or similar material, B, which has a hole Into which is inserted a stainless steel tube, C. containing a stabilized thermocouple D.
The polyethylene tube A is 6mm long. 4mm in internal diameter and has a wall thickness of 1 mm. The locating part of block B is 4mm in diameter and 2 mm high. When assembled, the two components form a specimen well 4 mm high 4 mm In diameter. In order to facilitate removal of the specimen after testing, the thermocouple 0 has a conical tip tisat protrudes 1 mm Into the base of the specimen well. The tolerances on the above-mentioned dimensions are ± 0.1 mm.
The thermocouple consists of wires (0,25 ± 0,05) mm in diameter, made 01 a material (e.g. copper/constantan) capable of registering rapid temperature changes In a specimen of setting material to an accuracy of 0.1 “C. The thermocouple is connected to an instrument (e.g. voltmeter or chart recorder) capable of recording the temperature to that accuracy.
NOTE A prefabricated thermocouple or similar sisr and performance can b substituted.BS EN ISO 6874 pdf download.